It doesn't matter what any "Brussels bureaucrats" say.
To rejoin we'd need the unanimous approval of all 27 member states. Any one of them could veto us. There would have to be referendums in at least four countries. I'm pretty certain France would vote no.
And the "Brussels bureaucrats" know this. They know there's no chance of us being approved to rejoin so they have nothing to lose by saying we're welcome back any time just to look nice.
The electoral suicide for a UK PM wouldn't be from trying to take us back in. (In any case there would be a referendum on it.) The real electoral suicide would be from giving us the option to rejoin, the electorate voting yes (which I think we would) and then being unable to deliver because other countries said no.
Anyway. That's by the by.
I think trans stuff is more dangerous because so many people still don't have a clue what it all means and think it's about being kind.